View full sizeRepublican U.S. Sen. Scott Brown's campaign will donate to a charity chosen by Democratic rival Elizabeth Warren's supporters after a third-party was found to be advertising on his behalf in violation of the "People's Pledge" agreement. (AP photos)

"After learning a third-party group was running Internet ads on behalf of Scott Brown, the Brown campaign agreed to honor the terms of the pledge with a donation to a charity of Professor Warren’s choosing," said Colin Reed, a spokesman for the Brown campaign on Tuesday. "Today, Scott Brown’s People’s Pledge worked exactly as intended."

"We've just learned that a pro-Mitt Romney PAC was caught running ads on Google in support of Scott Brown," the campaign said in the email. "The Brown campaign has agreed to donate 50% of the value of the advertising spend to a charity of our choice, as outlined in the pledge. This is the People's Pledge -- so we'd like your help picking the charity Scott Brown donates to."